Bound By Blood
by ThisCatalyst'sPen
Summary: The effects of the mutagen are starting to turn deadly. With his brothers falling sick around him one by one, Don must find a cure to stabilise the mutagen before he and his brothers perish. Racing against the clock, Don needs to find a solution, but whilst studying their blood and DNA, Don learns more about his family, and his heritage then he ever thought he would.
1. Chapter 1 First Strike

**Summary:**Something is happening to the turtles. The mutagen they fell into all those years ago is slowly starting to change. The effects of the mutagen are starting to turn deadly. With his brothers falling sick around him one by one, Donatello must find a cure to stabilise the mutagen before he and his brothers perish. Racing against the clock, Don needs to find a solution to his family's predicament before time runs out. But along the away, whilst studying their blood in hopes for a cure, Don learns more about his family, and his heritage then he ever thought he would.

**Disclaimer: **Insert the usual, I do not own TMNT. All I own is an idea. The characters and rights all belong to their respective owners; I'm just having some fun.

**Author's Note: **Hello all! *runs away and cringes in corner* I am so, so, so sorry for the awfully long delay and no updates to my previous stories. I can give you the usual excuses of life being hella' busy, as usual, but in truth, I have all but lost my inspiration which is devastating. I hope a new idea will get me back on track but I cannot make any promises nor can I promise regular updates, however I shall do the best that I can.

I want to thank everyone for your continued support with my work and you undying patience. I hope that this story will play a small part in making up to you the lack of updates and commitment over the past few months.

Some things to know about this story; it will (hopefully) be a series. I have had this idea running around in my head for a while and have written a few chapters here and there and finally decided I should post the first part. So, this is technically *book* 1 in what I hope will become the 'Bound By' series. So please enjoy *book* 1, Bound By Blood. Apologies for the rambling author's note. Now please sit back and enjoy.

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><p><strong>Chapter One:<strong>

_First Strike_

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><p>Raphael woke up with a splitting headache. It felt like he had been hit by a bus. Every sound revibrated through his skull and made him cringe in pain. His temples felt like they were being crushed in a vice and behind his eyes, it felt like there was a miniature Satan drilling into his skull.<p>

"Ugh," Raphael mumbled, slowly sitting up in his hammock. The faint light in his room almost blinded his suddenly super-sensitive eyes, burning holes straight through his retinas. Each movement he made sent a stab of pain straight to his temples, making Raphael want to grip his head in his hands and scream. He had never had a migraine before, but he guessed this is what it felt like to have one.

With that thought in mind, he wanted nothing more than to curl up in his hammock, shut his eyes tightly and stay in bed forever. But the rational part of him told him to go find Donnie, and take some pain medication. Raphael hated taking pills. He didn't like having his reactions lulled by sedatives and unknown chemicals. But right now, Raphael didn't care. He just wanted the unbearable pounding in his head to stop.

Slowly, ever so slowly, Raphael placed his feet on the ground. Taking deep breaths, he prepped himself for what was about to come next, and slowly, ever so slowly, stood up. The pain hit him instantly, like he knew it would. He swayed dangerously on his feet; his head feeling like it weighed a million pounds. White spots dotted his vision and for a moment he thought he was going to pass out. Forcing himself to take deep, slow breaths, the overwhelming dizziness slowly went away and his vision returned to semi-normal. It still hurt to open his eyes and with every step he took, Raphael thought he was going to puke his guts up, but he forced himself to keep going, putting one foot in front of the other. He had to lean against the wall for support, and stop several times as another bout nausea and sudden waves of dizziness overtook him.

It felt like hours had passed by the time Raphael finally made it into the kitchen. It had taken him over five agonising minutes just to make it down the stairs, each jolt sending stabs of pain lancing through his skull.

Mikey was already at the table eating breakfast, a bowl of brightly coloured cereal drowning in a sea of milk sat in front of him. Mikey looked up from his breakfast mid-chew as Raphael entered the room, a frown forming on his features at the sight of his older brother.

"Hey dude, are you okay? You look like death," Mikey said around a mouthful of food, dribbling milk down his chin.

"Thanks, Mikey," Raphael grumbled, not having the energy to say anything witty back. "I got a killer headache; do you know where Don is?"

"He's in his lab, as usual," Mikey said, swallowing another mouthful of cereal. "Do you want me to make you some breakfast? There's still a bit of cereal left."

"No thanks, Mikey," Raphael replied, slowly shuffling in the direction of Don's lab. "If I eat anything I'll puke."

Raphael slowly made his way to Don's lab. Cringing from the insistent pounding in his head, Raphael stopped and leaned against the closed door, trying not to pass out. The sound of typing came from inside the dimly lit room. Raphael leaned heavily against the doorframe, fighting down the bout of nausea that attacked him, before pushing the door open. Don looked up from his computer, his face illuminated in the faint blue glow. A look of worry crossed his features when he saw Raphael.

"Raphael, are you ok?" Donnie asked, quickly getting to his feet.

"I'm ok, Donnie," Raphael assured his brother, stumbling into the room. "I have a killer headache though. You got any pain meds?" He felt light headed and the pounding in his skull was reaching a crescendo.

"Of course," Don said, moving to rummage through the medicine cabinet on the far wall. "Take a seat," he said, gesturing to one of the spare chairs in the room. "I want to check you over."

"I told ya', Donnie, I'm fine," Raphael assured his brother, taking a seat nevertheless. "It's just a bad headache."

"I'm sure it is, I just want to be sure," Don explained, grabbing what he was looking for out of the cabinet and making his way over to Raphael.

"Follow the light with your eyes," Don instructed, crouching down in front of his brother and shinning a small torch into Raphael's eyes.

"Agh," Raphael mumbled, raising a hand to shield his eyes from the sudden bright assault.

"Hmmm, just as I thought, you have a bad migraine," Donnie confirmed.

"Told ya," Raphael mumbled, his eyes still hurting from the harsh light.

"Take two of these," Donnie instructed, handing Raphael two white pills. "It should help. I'll get you a glass of water to wash them down with."

"Thanks, Donnie," Raphael mumbled weakly after his brother.

Don returned quickly with a glass of cold water. Handing it to Raphael, he made sure his brother swallowed both of the pills; he knew what Raphael was like when it came to taking medicine. "Now, you can have another two in four hours," Don explained. "You'll need to rest, so no training for you today. Try to sleep if you can and keep drinking. I'll check up on you every two hours. If you need anything or if it gets worse, let me know."

"Thanks, bro," Raph said, getting shakily to his feet.

"You can crash on the lounge if you want," Don suggested. "I'll tell Mikey he has to keep quite."

"Good luck with that," Raphael mumbled, managing a weak smile.

He slowly made his way over to the couch, gingerly lowering himself on the sofa cushions.

Raphael curled up on the couch, squeezing his eyes shut and waited for the pain meds to kick in. Don had told Mikey to keep quiet, and so far, his youngest brother was surprisingly complying. Raphael hadn't heard a peep out of the orange-banded turtle, for which he was grateful. Don had also told Master Splinter and Leo the condition he was in and they had excused him from training for the day, another thing Raphael was thankful for. But no matter how much he tried, he couldn't sleep. The pain in his head wasn't going away. If anything, it felt like it was only increasing. He felt nauseas and dizzy and couldn't move without the threat of passing out. He kept his eyes squeezed shut, forcing himself to take slow and even breaths. He felt like death and prayed that the drugs Don had given him would take affect soon.

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><p>When Raphael awoke the lair was in darkness. Blinking in confusion, Raphael pushed himself into a sitting position, waiting for his eyes to adjust to the gloom. He noticed that his headache was almost completely gone. The dizziness and nausea he had felt was no longer present. He had no idea how long he had been sleeping for, but the quietness and darkness of the lair indicated that it had been for quite awhile.<p>

"Good, you're awake," Don's voice came from the shadows of the room.

Raphael looked around, his eyes quickly adjusting. Don leaned down next to him, a small smile on his face.

"How long have you been here for?" Raphael asked, his voice hoarse.

"Three hours," Don replied. "I wanted to see you when you woke up."

"How long have I been out for?" Raphael asked, sitting up on the couch.

"All day and most of the night," Don answered. "It's two a.m."

"Damn," Raphael muttered, "what did you give me?"

"Only Aspirin, I promise," Don chuckled. "It's good that you got some sleep though. I came to check on you earlier and you were fast asleep. I didn't want to wake you."

"Well, that Aspirin you gave me is a miracle cure," Raphael said. "My headache is almost completely gone."

"That's strange," Don said with a slight frown. "From what I saw this morning, you had a pretty sever migraine. I only gave you two Aspirin- that was a pretty quick recovery."

"I ain't complaining," Raphael said. "It was shit."

"I bet it was," Don sympathised. "Don't get me wrong, Raph, I'm glad you're feeling better too, it's just strange that it happened so quickly, that's all."

"Maybe you slipped me the wrong pills," Raphael joked, his voice still hoarse.

"Maybe," Don smiled. "Stay here, I'll get you some water."

Raphael stretched his cramped limbs. He felt oddly re-energised.

"Here," Don said, returning from the kitchen with a cold glass of water.

"Thanks," Raph said, accepting the glass and gulping the cold liquid down quickly. The coolness of the water soothed his hoarse and aching throat. It felt wonderful. Raphael's stomach chose that moment to growl, letting both him and Don know that it was hungry.

"You must be hungry," Don chuckled. "You haven't eaten a thing all day."

"Yeah, starving," Raph agreed. Slowly, he got to his feet. No wave of dizziness or nausea assaulted him, so he took that as a good sign. Don followed him to the kitchen, standing close beside him in case he fell.

"There's some pizza left over in the fridge," Don said. "Peperoni, I think."

"Sweet," Raphael said. Peperoni was his favourite.

Grabbing the box from the fridge, Raphael took it to the table and sat down, eating it cold. He liked cold pizza the best. He cautiously ate one slice, chewing slowly, waiting to see if he would vomit it back up again. But the pizza stayed in his stomach so he quickly ate the rest, feeling the day's hunger.

"Well, I'm impressed," Don said when Raphael had finished. "I guess Aspirin and sleep really does help."

"Ha, yeah, I guess," Raphael chuckled. "Thanks for staying up with me, Donnie, and making sure I was alright."

"It's okay, Raph, I'm glad you're feeling better," Don smiled.

"Get some sleep, Donnie," Raph said. "You need some rest."

"What are you going to do?"

"I'm gonna hit the showers," Raph said, getting to his feet.

"Okay, let me know if you need anything," Don said.

"I will, thanks, Don."

Raphael made his way to the bathroom and closed the door behind him. He had always found the shower to be a place of peace and solitude. The warm water washed away the dirt and grime of the day, and on some days, blood, both his own and a strangers'. Raphael turned on the faucets and stripped his gear off before stepping under the stream. The hot water cascaded down his shell, steam quickly rising in the air. Raphael sighed in content, feeling his muscles begin to relax under the hot stream. He always felt relaxed in the shower, must be the turtle side of him relishing in the water.

After a few minutes, Raphael turned off the faucet and reached for his towel. A sudden wave of nausea hit his stomach and a sharp pounding in his head flared back to life. Raphael grunted in pain and surprise, stumbling forward, leaning on the tiled wall for support. His vision went blurry as white dots danced in front of his eyes. Raphael groaned and gripped his suddenly pounding head in pain.

Maybe his migraine wasn't completely gone after all.

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><p><strong>Author's Note 2: <strong>Well, I hope you all enjoyed this little teaser slice of what I hope will turn out to be a series. I would love to know what you thought; a review would be very kind :)

If you have any questions/comments/qualms, please feel free to comment in a review or PM me.

Until the next time,

~Cat


	2. Chapter 2 Pride Before Fall

**Summary:**Something is happening to the turtles. The mutagen they fell into all those years ago is slowly starting to change. The effects of the mutagen are starting to turn deadly. With his brothers falling sick around him one by one, Donatello must find a cure to stabilise the mutagen before he and his brothers perish. Racing against the clock, Don needs to find a solution to his family's predicament before time runs out. But along the away, whilst studying their blood in hopes for a cure, Don learns more about his family, and his heritage then he ever thought he would.

**Disclaimer: **Insert the usual, I do not own TMNT. All I own is an idea. The characters and rights all belong to their respective owners; I'm just having some fun.

**Author's Note: **Thank you for the positive feedback for the first chapter, I'm glad you are interested. I hope you all enjoy this chapter as well.

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><p><strong>Chapter Two:<strong>

_Pride Before Fall_

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><p>Leo watched his brother with keen eyes, worry worming an insistent knot in his gut. It had been three days since Raphael had been sick, and his brother showed no sign that he was improving. Don was just as worried as Leo. Raphael's migraine would come and go, as unpredictable as the city's train times. One minute, Raphael would have a pounding headache that brought him to his knees in pain, then the next minute, it was over, and there were no signs that anything had happened. He would be able to join in training one day and the next he would be lying on the couch in agony, unable to move. Tonight they were going over to see Casey and April, and were having dinner with them. Don was reluctant for Raphael to go, considering the un-expecting nature of his headaches, but at the same time he thought some fresh air might be good for him. Besides, he knew Raphael would come anyway, with or without their permission.<p>

At the moment, Raphael was fine. He showed no signs that the headaches were back and he was easily keeping up with the slow pace Leo had set. He seemed to be enjoying himself as well, laughing and chasing Mikey across the rooftops; which compared to yesterday, when he couldn't move at all, was quite an astonishing improvement. Donnie was at a loss as to the strange nature of Raph's on and off migraines. He gave Raph Aspirin when he needed it and monitored his vital signs, but there appeared to be no life-threatening signs to follow. It seemed that Raphael just couldn't quite get rid of his headache altogether.

Donnie had briefly wondered if it was a phase his body was going through, an odd growth spurt of some kind, but he couldn't be sure. For the moment, all they could do was ride it out as best they could.

It was a peaceful night, and Leo stopped for a moment to enjoy it. The sky was clear and even through the light pollution of New York City; Leo could see the full silver moon shinning down on them, surrounded by a cluster of shining stars, like glitter in the sky. A cool breeze kissed his skin and the promise of summer could be smelt in the fresh air.

"It's a nice night," Raphael mumbled, suddenly standing beside his brother.

"It is," Leo agreed, before looking over at his brother with worry. "How are you feeling?"

Raphael raised an eye-ridge. "I'm fine, Leo. Haven't had a headache for nearly eight hours now."

"That's great," Leo said, enthused. "Maybe the fresh air is doing you good."

"Yeah, maybe," Raphael agreed with a small grin.

"Now, Raph..." Leo began.

"Here it comes," Raphael rolled his eyes. "What is it, Leo?"

"I know you like hanging out with Casey and having some fun, just promise me you'll take it easy tonight, okay? I don't want you doing anything that might make whatever this is, worse."

Raphael sighed but met Leo's unwavering gaze evenly. "Alright, Leo, I promise."

"Thank you, Raph," Leo said, a little surprised at the lack of fight Raphael showed. "Now come on, April said she's making a mean roast for dinner."

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><p>"Mmmm, that was delicious, April!" Mikey exclaimed with enthusiasm, licking his lips as if to prove his point.<p>

"Why, thank you, Mikey," April laughed. "I'm glad you enjoyed it."

"April's a killer at roast," Casey agreed, sitting back in his chair and patting his well-fed stomach. "Ain't ya' babe?"

"Don't call me babe," April retorted with a playful grin.

"So, what's for desert?" Mikey asked hopefully.

"Hold your horses there, Mikey," Leo interrupted. "Give us a few minutes to digest what we already ate. Why don't you clean up for April?"

Mikey's face paled at the suggestion and a look of horror crossed his features. "Clean?" He asked disbelievingly.

"Yes, Mikey," Don said sternly. "April worked very hard to make us this beautiful dinner, the least you can do is clean up after it."

"But what about you guys?" Mikey demanded. "Why don't you have to help?"

"'Cause," Raphael said, leaning back in his chair, "we ain't tha' ones complaining about desert."

"Come on, Mikey, I'll help," April offered. "If you wash, I'll dry."

"You don't have to do that, April. I can help," Don quickly offered.

"It's okay, Donnie," April assured him. "I really don't mind. Besides, it means I can keep an eye on Mikey to make sure he doesn't eat the desert without us."

"Hey!" Mikey complained with indignation.

"It's okay, Mikey, I'm just teasing," April laughed, pushing the reluctant turtle into the kitchen.

"So, how have things been?" Leo asked Casey once April and Mikey had disappeared into the kitchen. "Being a married man."

"It's good," Casey said, leaning back in his chair with a content smile. "I don't see what guys complain about."

"That's cause you just got married," Raphael smirked. "Just you wait. Soon you'll have to settle down, get a day job, wear a tie."

"Whoa, whoa, whoa, ain't no one making Casey Jones wear a tie," Casey said quickly. "That's not my style. I prefer the o' natural look."

"He's teasing, Casey," Don assured him. "Marriage isn't like that. Not that I know from experience or anything, but Raph's just stirring."

Raphael shrugged. "You still allowed out? You know, patrolling and whatnot," he asked his friend.

"Yeah," Casey assured him. "Look, just because we're married doesn't mean April's asking me to give up being me. She understands, that's one of the things I love about her."

"Awe," Raphael said, battering his eyes.

"Hey," Casey grinned, punching Raph's arm, "I ain't gone soft or nothing."

"What about when April decides that, you know, she wants to start a family?" Leo asked casually.

Casey choked on his beer, spitting it all over the table in surprise. "It's a little early to start thinking about that, don't you think?" Casey said between coughs.

"It was a joke, Casey," Leo assured him. "There's plenty of time to think about that in the future."

"Don't tell Mikey," Don warned, "He won't shut up about being an uncle otherwise."

Raphael smiled at his brothers' antics before a frown slowly replaced his smile. He felt a pounding begin in his temples, quickly manifesting in intensity.

"Not again," he whispered to himself, pushing away from the table and quickly getting to his feet.

"Raph, are you okay?" Leo asked in concern, seeing his brother's demeanour change.

"Yeah, I'm fine," Raphael reassured him quickly, hoping the pounding in his skull would only be fleeting. "I'm just going to get some air."

Raphael quickly walked out of the room and made his way over to the living room window. He hadn't made it halfway across the room when he suddenly doubled over in pain, gripping his pounding skull in his hands like it might explode.

Leo looked over his shoulder and leapt to his feet when he saw his brother. "Raph, are you okay?" Leo cried out in worry, quickly making his way over to his brother.

A ragged cry of pain tore free from Raphael's throat as he fell to his knees, a trail of bright crimson blood slowly leaking from the corner of his mouth. "Leo, something's wrong," Raphael gasped through the unbearable pain.

He was briefly aware of his brothers kneeling in front of him, reaching out for him in concern, but his vision turned blurry and he couldn't hear what they were saying. Suddenly his muscles seized and pain lanced through his body. Raphael screamed in agony, his limbs jerking wildly as he hit the floor hard. He was aware of panicked shouting all around him, and someone's hands were on his shoulders, trying to hold him down, but then his vision dipped and he fell into the waiting darkness.

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><p><strong>Author's Note 2: <strong>Not good news for poor Raphie. I hope you all enjoyed this chapter and are intrigued enough to keep reading. I would love to know what you thought; a review would be very kind :)

If you have any questions/comments/qualms, please feel free to comment in a review or PM me.

Until the next time,

~Cat


	3. Chapter 3 Plunge into the Unknown

**Summary:**Something is happening to the turtles. The mutagen they fell into all those years ago is slowly starting to change. The effects of the mutagen are starting to turn deadly. With his brothers falling sick around him one by one, Donatello must find a cure to stabilise the mutagen before he and his brothers perish. Racing against the clock, Don needs to find a solution to his family's predicament before time runs out. But along the away, whilst studying their blood in hopes for a cure, Don learns more about his family, and his heritage then he ever thought he would.

**Disclaimer: **Insert the usual, I do not own TMNT. All I own is an idea. The characters and rights all belong to their respective owners; I'm just having some fun.

**Author's Note: **Thank you for the positive feedback so far! I am not sure if I will be able to post another chapter before Christmas/New Years but I'll see how I go :)

* * *

><p><strong>Chapter Three:<strong>

_Plunge into the Unknown_

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><p>Raphael awoke to the sound of concerned voices.<p>

_He's been unconscious for nearly two days now_

_Donnie, do you have any answers yet?_

_Give him room to breathe, Mikey, I think he's coming to_

_Raph, Raph, can you hear me?_

"Ugh, what happened?" Raphael groaned. "I feel like I've been hit by a bus." He said in a groggy voice.

He tried to open his eyes but his body felt like it was weighed down with sandbags. His eyes felt extremely heavy, and the harsh pounding in his skull discouraged any movement. Slowly, he forced his eyes open, blinking to adjust to the harsh light that assaulted his pupils.

"Take it easy, Raph," a soothing voice said, warm hands touching his shoulders.

Strengthened by the warm touch of his brother, Raphael forced his eyes open, blinking through the bleary haze that greeted him. He was in his room, lying in his bed, propped up slightly with pillows. His brothers stood around him, all wearing similar looks of concern.

"How are you feeling, Raph?" Donatello asked, crouching beside his brother and checking him over.

"Like I said, feel like I've been hit by a bus," Raphael grumbled, trying to wave Don's concern away. "So what happened?"

"I think you experienced a seizure," Donatello explained, stepping back to give Raphael room to sit up. "Do you remember much of what happened?"

Raphael frowned. "I remember being at April's and getting a headache again. That's it."

"You got another migraine," Don explained, "though it was the worst one yet. Your muscles started to seize and you passed out. We brought you back here straight away. You've been unconscious for nearly two days now."

"Two days..." Raphael trailed off in disbelief. "What's...what's wrong with me, Donnie?"

"I don't know, Raph," Don replied truthfully with a pained sigh. "I've taken some blood for testing, but the results won't be conclusive for at least twelve hours. Until then, I need to monitor your vitals and do a few simple tests so I can try to figure out what is happening."

"What are you feeling now?" Leo asked. "Do you still have a migraine?"

"I feel better than I did before," Raphael assured his brothers. "I still have a headache and my body hurts, but it's not as bad as before."

"Your muscles are probably still cramped from the seizure," Don explained. "Which is probably why you feel sore and don't want to move."

"Kind of hungry too," Raphael added as an afterthought.

"I'll make you something," Mikey said quickly, eager to help.

"Thanks, Mikey," Raph said as his brother quickly left the room.

"I won't know the cause of the seizure until the blood results are in," Donnie said once Mikey had left the room. "There is more than one cause for a seizure to occur. It could be anything from low blood sugar to kidney or liver failure. The constant migraines on the other hand, I really don't know."

"It could be induced from higher levels of stress," Leo suggested.

"I haven't been stressed, though," Raphael said. "Not really. I mean Mikey's a pain in the butt, but he's not _that _bad."

"Hopefully the blood results will enlighten us," Don said. "For now though, you need to get some food and fluids into you. I will have to monitor you hourly to make sure you don't experience another seizure and to keep your migraine under control. You need plenty of rest and I will give you some strong pain medication- hopefully that will help for the time being, at least until I can get some answers."

Mikey walked back into the room, a tray of delicious smelling food in his hands.

"I didn't know what you felt like, or how hungry you were, so I just got a bit of everything," Mikey explained, placing the tray of food on Raphael's lap.

"Wow, Mikey…this looks delicious," Raphael said, taking in the plethora of food on his plate. Mikey had cooked him strips of bacon, eggs, buttered toast, yogurt and a bowl of fresh strawberries. "You didn't have to do all this, Mikey," he said gently but gratefully.

"It's okay," Mikey shrugged. "I wanted to help."

"Try and eat as much as you can," Don encouraged, setting a cold glass of water down beside him. "And keep drinking, you need to stay hydrated."

"I feel like the mother of three on mother's day," Raphael snorted taking a bite out of his toast. He chewed it slowly, the warm, buttery taste melting over his tongue. He swallowed his first bite and waited. It didn't come back up. Encouraged by this fact, Raphael eagerly tucked in with gusto.

"Didn't realise how hungry I was," Raphael said in-between bites.

"Like I said, you've been unconscious for nearly two days," Don pointed out with a smile. "I'd be worried if you _weren't _hungry."

"April and Casey called earlier," Leo said, "they wanted to know how your feeling."

"I feel bad," Raphael said, "flaking out on them like that."

"Don't be silly," Don assured him. "They're concerned about you, we all are."

"Well, it's okay, I'm fine now," Raphael reassured his brothers. "At least, I think I am. I feel fine at the moment."

"Good, let's hope it stays that way," Donnie said.

"I'll call April and let her and Casey know," Leo said, walking towards the door.

He made it halfway across the room before he stopped, gasping in sudden pain.

"Leo, what's wrong?" Don asked, moving over to stand beside Leo.

"Nothing, I'm fine," Leo assured him quickly. "I think I'm just a bit tired, I can feel a headache coming on."

"Get some rest," Don said firmly. "I'll call April and let her know. I don't need two of you in here complaining about headaches."

"Thanks, Donnie," Leo smiled gratefully. "Let me know if anything changes with Raph."

"Don't worry, I will," Don assured his brother. Walking out into the kitchen, Don picked up the phone and dialled April's number.

"Hello, April speaking."

"Hey, April, it's Donnie."

"Hey, Don, how's Raph?"

"Better, he woke up not too long ago. Dazed and confused, but a lot better than he was the other night."

"Do you know what caused it?"

"Not yet, still waiting for the results from the blood test. I should know tomorrow."

"I hope it's nothing serious. If you need help of any sort, Casey and I are happy to help in whatever way we can."

"Thanks, April," Don smiled through the phone. "I'll be sure to let you know. But for now everything's okay."

"That's good. I'll let Casey know, he's been worried sick about Raphael, not that he'd ever say so out loud."

"Haha, he has too much pride for that," Don laughed.

"Thank you for calling me, Don."

"It's okay, thank you for all your help."

"You're welcome, Donnie. I'll see you later."

"Bye," Don hung up the phone and sighed. He didn't realise how tired he was.

"I'll look after Raphie, if you want to grab some sleep," Mikey offered.

"You sure, Mikey?"

"Yeah," Mikey assured his brother. "I've got this. I'll wake you up if anything happens."

"Thanks, Mikey," Don smiled.

"Sure. Now go get some sleep. I've got this covered."

* * *

><p><strong>Author's Note 2: <strong>I hope you all enjoyed this chapter and are intrigued enough to keep reading. I would love to know what you thought; a review would be very kind :)

If you have any questions/comments/qualms, please feel free to comment in a review or PM me.

Until the next time,

~Cat


	4. Chapter 4 Tiredness Can Kill

**Summary:**Something is happening to the turtles. The mutagen they fell into all those years ago is slowly starting to change. The effects of the mutagen are starting to turn deadly. With his brothers falling sick around him one by one, Donatello must find a cure to stabilise the mutagen before he and his brothers perish. Racing against the clock, Don needs to find a solution to his family's predicament before time runs out. But along the away, whilst studying their blood in hopes for a cure, Don learns more about his family, and his heritage then he ever thought he would.

**Disclaimer: **Insert the usual, I do not own TMNT. All I own is an idea. The characters and rights all belong to their respective owners; I'm just having some fun.

**Author's Note: **I hope everyone had a Merry Christmas and are enjoying their holidays :) Bring on the new year! It should be full of updates and exciting new stories! Thank you for patiently waiting for an update during this busy time of year. I hope it was worth the wait.

* * *

><p><strong>Chapter Four:<strong>

_Tiredness Can Kill_

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><p>Donatello could barely keep his eyes open. He hadn't gotten a lot of sleep the past two days. His brain felt like it had been hot-wired. Thoughts raced incoherently through his mind, never stopping to give Don a chance to analyse them. His body was running on empty, and it wouldn't be long before his body gave in to the consequences. There was only so much coffee could do, after all.<p>

Don looked up from the pages upon pages of hastily scrawled notes littering his desk and sighed, rubbing his tired eyes and pounding head. It took all of his will power and ninja training to keep his eyes open. They felt like someone had rubbed them with a handful of sand, and felt weighed down by sandbags. He desperately wanted to sleep, to curl up on his bed and give in to the darkness, but he knew he couldn't. He shrugged the weak thought away and reached over for his ever-present coffee mug, raising it to his lips. It was empty. It had been empty for over an hour now. He was contemplating getting up to make another coffee- his tenth, fifteenth? – coffee of the night when he remembered that he had used up the last of the precious substance. He would have to call April for an emergency coffee run.

Checking the clock on his computer, Don realised that several hours had passed since he had last checked. The blood sample he had taken from Raph earlier would be ready. Getting to his feet, Don went over to the far side of his lab and retrieved the blood sample. Taking the vial of crimson liquid back over to his desk, Don set up his microscope and prepared a sample. Leaning forward, he pressed his eye to the glass and studied the blood sample.

At first, there didn't seem to be a notable difference in the blood. Turning the focus knob and increasing the magnify level, Don squinted again at the blood sample. A frown slowly started to crease his features as he studied the blood with more depth.

"What on earth…" Don muttered.

"Oh no," he whispered, leaning back away from his desk. "This isn't good."

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><p>After studying the blood sample for another two hours, Don could no longer deny that the results were conclusive. He knew he couldn't put the news off any longer and summoned everyone into Raphael's room. They stood there now, fidgeting on the spot, waiting for Donnie to deliver the news.<p>

Mikey was the first to break the silence. "So…do you know what's wrong with Raphie?"

"I do," Don answered slowly, unsure how to tell his brothers of the discovery he had made.

"Well, go on," Raphael growled in impatience from where he was propped up in bed. "Get it over with already." He looked pale and weak, his face drawn and his eyes heavy with pain and fatigue.

Don slowly exhaled the breath he had been holding before reply. "The blood analysis showed that the mutant cells in Raph's body are fighting his non-mutated bodily cells."

"Wait...what?" Mikey asked, already confused.

"When we were exposed to the Mutagen," Don explained, "the Mutagen didn't infuse with our own cells but created cells of their own, so that we have two pairs of different cells in our bodies. Now, however, the Mutagen cells within Raph's body are fighting his normal bodily cells for dominance."

"What does that mean?" Leo asked, worry tinging his voice.

"It means the mutagen cells are attacking the rest of Raphael's cells. If...if this continues to happen, eventually the mutagen cells will win, as they appear to be stronger, and...And Raph will die."

A shocked silence filled the room.

"So the thing that gave me life is now killing me?" Raphael growled in disbelief, pushing himself up.

"In a way, yes," Don replied slowly.

"Well I'm not going to just lay here and wait to die," Raphael said, his anger giving him energy enough to push himself from his bed to his feet.

"Raph, lie down!" Leo ordered, pushing his brother gently but firmly back on his mattress. "This doesn't change anything; you are still too weak to be up and about."

"I don't care; I'm not going to just sit here and wait to die!" Raphael said angrily, fighting Leo's hold.

"You're not going to die," Don said firmly. "I'm going to find a solution."

"We'll help, Donnie," Mikey said instantly, worry and fear clouding his soft blue eyes. "We'll do anything, just tell us what to do."

"I need to do some more conclusive tests first, to figure out why this is happening," Don explained. "Once I've done this, I can work out how much time we have and find a cure."

"And what, I'm supposed to just sit here twiddling my thumbs while all of this is happening?" Raphael demanded angrily.

"Yes," Don said firmly. "Like it or not, Raph, you are too weak to do anything at the moment. If you strain yourself, you could bring on another seizure, and this time you might not recover from it. Apart from constant headaches, we don't know what other toll this could have on your body."

"We'll keep you updated," Leo assured him. "We won't leave you here sitting in the dark. We _will _find a solution. No one's dying here, not on my watch."

* * *

><p><strong>Author's Note 2: <strong>I hope you all enjoyed this chapter and are intrigued enough to keep reading. I would love to know what you thought; a review would be very kind :)

If you have any questions/comments/qualms, please feel free to comment in a review or PM me.

Until the next time,

~Cat


	5. Chapter 5 Making Matters Worse

**Summary:**Something is happening to the turtles. The mutagen they fell into all those years ago is slowly starting to change. The effects of the mutagen are starting to turn deadly. With his brothers falling sick around him one by one, Donatello must find a cure to stabilise the mutagen before he and his brothers perish. Racing against the clock, Don needs to find a solution to his family's predicament before time runs out. But along the away, whilst studying their blood in hopes for a cure, Don learns more about his family, and his heritage then he ever thought he would.

**Disclaimer: **Insert the usual, I do not own TMNT. All I own is an idea. The characters and rights all belong to their respective owners; I'm just having some fun.

**Author's Note: **Happy New Years everybody! I hope everyone has an amazing new year and may all of your resolution come true ;) I want to thank you all for the positive feedback I have had with this story so far. I am so glad you are all enjoying it. I hope you enjoy this chapter as much as the rest.

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><p><strong>Chapter Five:<strong>

_Making Matters Worse_

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><p>Leo was trying to stay out of Don's way. The genius was rushing around his lab, searching through piles of books and half finished machines that lay scattered all over every available surface within the room. Leo wanted to help Don in any way he could to figure out a solution, but being surrounded by so many things he didn't even know the name of, or understand their function, Leo wasn't quite sure any more how he was going to do that. Mikey was still happy to look after Raph, spending all his free time with his sick brother. Leo knew Raph wasn't happy about the situation, and was more unhappy with not being able to do anything, but he knew it was for his own good, no matter how stubborn he was.<p>

Leo looked around for something to do. Don was bent over a microscope, peering at the slide underneath with a critical eye. Leo leaned forward to try and see what his brother was examining.

"If you want to help, Leo, you can bring me a tray of fresh beakers over," Don sighed, not looking up from his scrutiny.

"Beakers, right, sure," Leo said, looking around the room for the said objects.

"Over by the sink," Don said, as if he could see Leo's perplexed look.

"Right, thanks," Leo said, walking quickly over to the sink where the tray of beakers sat. Bringing the tray over, he sat it down carefully next to Don and stepped back, not sure what to do now that his menial task was complete.

"Thanks," Don said, not looking up from his microscope.

"No problem," Leo replied, stepping back to give his brother more room. All of a sudden his head began to ache and his vision swam. Thinking it was just a head spin, and it would pass in a moment, Leo leaned against one of the benches pushed against the wall for support. _I'm just tired,_ he thought. _I just need to get some rest_. However the pain didn't fade, it increased. What felt like an explosion erupted inside Leo's temples, making him gasp in pain and grip his head between his hands. His vision turned blurry and Leo thought for a moment, that he might pass out.

"Leo?" Don asked in concern, looking up from the microscope and seeing his ailing brother. "Leo, what's wrong?" he demanded, making his way over to his brother, his voice tinged with worry.

"I don't know," Leo admitted between clenched teeth. "I just got a headache all of a sudden."

"Here, sit down," Don ordered, guiding his brother over to a nearby chair.

Leo sat down heavily, his head still gripped between his hands. "Donnie, it hurts so bad."

"What are the symptoms?" Don asked, kneeling down beside his brother.

"Blurred vision, feeling faint and a really bad headache," Leo groaned.

"That sounds a lot like what Raphael was feeling the other day," Don mused to himself before going rigid. They _were_ the same symptoms. _Which means, _Don realised, _what's happening to Raph is going to happen to all of us…_

"What does it mean, Donnie?" Leo whispered, his eyes clenched shut with pain.

"It means," Don said slowly, "we're running out of time."

* * *

><p>Raphael couldn't help the groan that escaped his lips. The pain in his head was unbearable. He felt like his skull was being cracked open from the inside. He wanted to curl up into a little ball and never wake up; his whole body ached. His head pounded and felt like it weighed a million pounds. His vision was blurry, so Raphael kept his eyes tightly shut. His stomach heaved and he felt like he was going to be sick. He was starting to shake and his body was sleek with sweat.<p>

He felt Mikey's warm hand around his, squeezing tightly. Raphael squeezed back weakly, silently thanking Mikey for being here. Raphael usually hated for people to be around him when he was sick or injured. He didn't like them to see him weak and helpless, but at the moment, Raphael was in too much pain to care.

The door opened and Donnie entered the room, looking like hell.

"Donnie, what is it?" Mikey asked, getting to his feet.

Raphael could hear the concern in his brother's voice. Forcing his eyes open, Raphael tried to sit up. "What's going on?" He slurred, his tongue feeling like cement in his parched mouth. Mikey offered him a drink, and Raphael greedily gulped down the precious water.

"Leo's sick," Don said. "It appears that what's happening to you, Raph, is now happening to Leo."

"Where is he? Is he ok?" Raphael asked, trying to focus on his brother, but it was so hard, when his vision was so blurry.

"He's in my lab, resting," Don explained. "You need to lie down, Raph."

Raphael didn't argue and allowed Mikey to help him reposition himself on his bed. He was so tired.

"Wait, so why aren't we affected, Donnie?" Mikey asked in confusion. "Why haven't we felt any of the symptoms yet?"

"It must be something to do with our body structure," Don mused. "Size, age, weight, they could all be factors affecting the rate of the symptoms. Raph's the tallest and heaviest, hence the amount of Mutagen in his system will be slightly higher than ours, and Leo is the eldest."

"So, we haven't got this illness yet, whatever it is, but we will," Mikey concluded grimly.

"That's the way it seems to be appearing, yes," Don sighed.

"Do you know how to cure it yet?" Mikey asked hopefully.

"No," Don shook his head. "I was working on it but had to help Leo."

"So, what does this mean?" Mikey asked, glancing at Raphael who had slipped back into a fitful sleep.

"It means that we need to find out more about what this illness is and create an antibody, now, before it happens to us too."

* * *

><p><strong>Author's Note 2: <strong>I hope you all enjoyed this chapter and are intrigued enough to keep reading. I would love to know what you thought; a review would be very kind :)

If you have any questions/comments/qualms, please feel free to comment in a review or PM me.

Until the next time,

~Cat


	6. Chapter 6 Unexplained Intentions

**Summary:**Something is happening to the turtles. The mutagen they fell into all those years ago is slowly starting to change. The effects of the mutagen are starting to turn deadly. With his brothers falling sick around him one by one, Donatello must find a cure to stabilise the mutagen before he and his brothers perish. Racing against the clock, Don needs to find a solution to his family's predicament before time runs out. But along the away, whilst studying their blood in hopes for a cure, Don learns more about his family, and his heritage then he ever thought he would.

**Disclaimer: **Insert the usual, I do not own TMNT. All I own is an idea. The characters and rights all belong to their respective owners; I'm just having some fun.

**Author's Note: **Sorry for the wait for this chapter guys. I have been very busy with uni prep and will be pretty busy with that for a while. However I am still very keen on this story, so updates will be posted as regularly as I can. I hope you enjoy this chapter :)

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><p><strong>Chapter Six:<strong>

_Unexplained Intentions_

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><p>Donatello sighed in frustration, clapping his hands to his cheeks.<p>

"Donnie?"

Don looked up from where he sat perched on the end of his desk. Mikey looked at him with worry and concern from the doorway.

"Come in, Mikey," Don said, beckoning his brother forward. "What's wrong? Is something wrong with Raph?"

"No, Raph's fine," Mikey assured his brother, "so is Leo. They both fell asleep about half an hour ago."

"That's good," Don nodded. "They need their rest. Are you okay though?"

"Yeah, I'm fine," Mikey said with a casual shrug. "I just came to see how you were. Have you found anything more about the virus?"

"No," Don sighed in frustration. "I can't see any foreign bodies in their blood samples with my microscope. I need special equipment, equipment I don't have."

"Could you make the equipment you need yourself?" Mikey asked, knowing his brother was good with mechanics and engineering.

"No," Don shook his head sadly. "I don't have the materials, and it will take too long to make the equipment anyway."

"Can we steal it?" Mikey asked slowly, shifting his eyes to the floor, colour springing to his cheeks at the suggestion.

"No, I considered it though," Don replied, hoping to ease Mikey's guilt at the suggestion. "But it can't be found in hospitals. The only place I saw the equipment I need was in Baxter Stockman's old lab."

"So, you can't find a cure without the equipment?" Mikey asked.

"Yes," Don shook his head grimly.

"Maybe the equipment is still in the lab," Mikey suggested.

"I doubt it. Stockman abandoned his lab ages ago, and the Foot have probably already scavenged the place. Besides, we blew the place up, any equipment in there is probably destroyed."

"But we could try," Mikey persisted. "You never know."

Don thought about it for a moment. "Perhaps," he said slowly. "Though we both can't go, one of us needs to stay here to look after Leo and Raph."

"You can't go alone, Donnie," Mikey said. "It could be dangerous."

"Perhaps it's time to give Casey and April a call," Don said after a moment. "Maybe they can help."

* * *

><p>"Hello, April speaking."<p>

"Hey, April, it's Donnie."

"Hi, Donnie. How are you? How's Raph?"

"Raphael's still sick, and now Leo is too."

"What? How? Is it a virus?"

"It's complicated. I don't know a lot yet, or if there is a cure, that's what I'm trying to figure out," Don sighed. "But whatever it is, Mikey and I might get it too."

"That's horrible," April murmured. "If you need any help, Donnie, I'm always here."

"That's actually what I wanted to ask you," Don said. "I think the equipment I need is in Baxter Stockman's old lab. Mikey doesn't want me to go alone and someone needs to stay here with Raph and Leo. I was wondering if maybe you wouldn't mind coming with me?"

"Of course, Donnie. When did you want to go?" April asked.

"Tonight, if possible. Leo and Raph are pretty sick, and I want to find a cure before I get sick as well."

"I'll drive the van around in an hour," April said. "Casey can stay with Mikey and keep him company."

"That sounds good, April. Thank you so much."

"Anytime, Donnie. I'll see you soon."

"Alright, see you then."

* * *

><p>Baxter Stockman was a man who liked to be organised. He was punctual and precise in everything he did. Confusion and disorganisation annoyed him. He was annoyed now, watching the useless Foot soldiers scavenge through the junk of what remained of his old libratory after the cursed turtles blew it up. He clenched his jaw and bit his cheek as he watched the Foot carelessly toss aside the rubble and junk that remained. Sure, it was junk, but it was <em>his <em>junk.

He despised working with the Foot Clan and their leader, but their latest project could very well earn him millions, maybe even billions. He was willing to work with these miscreants if it meant he would soon be the richest man in the world.

"Come on, come on we don't have all day!" Baxter barked impatiently. He knew the job would probably go a lot faster if he helped the Foot in the search, after all, he knew better than anyone what they were searching for, but it was bad enough just being in their company, let alone lower himself to their level and dig through trash and scrap metal.

"The artefact has been found!"

Baxter snapped his head up at the approaching Foot ninja. "It is not an artefact, you fool! It's the key to making me rich." Taking the said artefact, Baxter held up his creation and searched it over for damage. Not even a scratch. He had made it durable, that was for sure.

"Come, we are finished here," Baxter said, hiding his creation carefully away inside his lab coat.

The sudden sound of voices echoed through the laboratory, causing Baxter Stockman to freeze. He knew those voices. The Foot had heard them too, and quickly had their weapons drawn in their hands. There were only ten Foot ninja, but by the sounds of the voices there was only one turtle. The odds appeared to be in their favour for a change.

"Well, well, well, what have we here?" Baxter called out, making their presence known.

The voices stopped abruptly. A minute of strained silence passed before the girl, April, stepped into view, quickly followed by the turtle in purple, the smart one.

"Baxter," Donatello said lowly, weapon in hand. "What are you doing here?"

"I could ask you the same thing, this is my lab after all," Baxter retorted, jutting his chin out. Narrowing his eyes he glanced at the several bags the pair carried. "But the answer appears obvious," he continued, "you're stealing from me."

"That's one way you could look at it," April said, taking a step forward. "But why are _you _here, Baxter? There's nothing left for you here but failed experiments and scrap metal."

Baxter bristled at the insult, before forcing himself to appear calm and aloft. "Oh, wouldn't you like to know?" He smirked.

"We don't have time for this," Don growled. "April, let's go, we'll worry about this another time."

"Someone appears to be in a rush," Baxter commented with a sly smirk. "Don't you want to know what we are up to? Why I'm working with the Foot?"

"Like I said, I have more important things to worry about," Don said, turning to leave with April in tow.

The Foot took a step after them, weapons raised, but Baxter gave them the signal to halt. This was far too interesting to end with a fight.

"I don't believe it!" Baxter barked a laugh. "The turtle is giving up. Now that's something you don't see every day."

Donatello stopped mid-stride, his hands clenching into fists at his side. He slowly turned his head to look over his shoulder at Baxter. "Oh, believe me, I will be back, and I will uncover whatever it is you are planning to do, Stockman. And believe me when I say, you will be sorry."

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><p><strong>Author's Note 2: <strong>I hope you all enjoyed this chapter and are intrigued enough to keep reading. I would love to know what you thought; a review would be very kind :)

Also note that this story doesn't follow any particular story line from the TMNT series, such as April once working for Stockman. However you will notice I am trying to incorporate different aspects from different series.

If you have any questions/comments/qualms, please feel free to comment in a review or PM me.

Until the next time,

~Cat


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